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'Fines' Are Not Fine in 'Flower Harvest

Thursday, August 1, 1996
filed under: Equipment

Dean Sonnenberg didn’t know what to think when, while harvesting sunflower one autumn evening several years ago, he first noticed small red flashes shooting past his combine windshield. “At first I thought I was just ‘seeing things,’ ” says the Fleming, Colo., producer. “Then I started looking for the problem.”

The “problem” was a smoldering fire next to a vertical wall beneath the combine cab. He was able to follow the red trail back to a guard atop the turbo, where a thick glowing layer of sunflower “fines” was readily apparent.

“I was accumulating dust around the turbo, and it was hot enough to start burning there,” Sonnenberg recalls. “Then the fan wash from the cooling fan was taking ‘chips’ of that, flipping them off, and they would fly around and land in other locations on the machine that had accumulated dust.

“That was the ignition method I was discovering.”

This nocturnal episode provided the northeastern Colorado producer’s introduction to the danger of fire while harvesting sunflower. It’s an experience many other sunflower producers have had at one time or another — particularly when combining low-moisture ’flowers. And it’s an experience which usually can be avoided, Sonnenberg and others affirm, with some straightforward housekeeping.

The main culprit is the small fibers or fuzz — “fines” — on the outside of sunflower hulls. Rubbed loose during threshing and then tossed around, these fines tend to accumulate on machine surfaces. Where those surfaces are extremely hot (e.g., the engine compart-ment), the fines can ignite, smolder — and, if in sufficient concentration and not controlled, sometimes burst into flames.

Clark, S.D., grower Vance Neuberger says it’s not unusual for him to average a half dozen or more smoldering hot spots each season while combining his 500 to 600 sunflower acres. He reports three potential problem areas on his JD 7720. “One would be in the engine compartment, where there can be a buildup of the fine dust. The sides and top of the feeder house can be a gathering place, too, due to debris and dust. Finally, at the front of the machine, when the platform is lifted, I’ll find concentrations in a hollow area on top of the fan housing.”

Combine manufacturers recommend — and Sonnenberg and Neuberger concur — that the best way to minimize the chances of smoldering or outright fires while harvesting sunflower is to simply keep one’s machine as clean as possible, not letting fines build up in potentially dangerous spots. “The fines really accumulate only in areas that are natural traps,” Sonnenberg says. “Either those areas are dead to air flow, or they have a lot of hoses, fittings, etc., around them.”

The High Plains producer’s solution has been to clean the combine thoroughly prior to the sunflower harvest season. He first blows off any loose dust, then takes a pressure washer and cleans the engine compartment “within an inch of its life.” Sonnenberg says he hasn’t had any fire problems since adopting the annual routine.

For Vance Neuberger, the cleaning habit is a daily one during the sunflower harvest. “Every morning, I take the air compressor and blow off those areas (engine compart-ment, feeder house, top of fan housing) as completely as I can before I go out to the field.” He figures the exercise sometimes takes close to an hour — but it’s worth every minute, Neuberger believes.

The South Dakotan takes some additional precautions. He has two large fire extinguishers bolted to the combine and readily accessible. He also carries a six-gallon container of water on board and has the garden hose ready at home so if he has a serious problem while in a nearby field, he can drive quickly to the yard and turn on the water.

Neuberger knows some producers have dragged a log chain behind their combine in the belief it reduces static electricity and thus the chances of fire. He doesn’t buy it. “A few years ago, I put on a rusty log chain and dragged it around. All I did was shine up the chain; I had just as many [smoldering] fires,” Neuberger reports.

Neuberger does believe that harvesting sunflower at a higher moisture content helps reduce fire risk. “I like to combine a little wetter — around 12 percent — than a lot of people,” he says. “You get a cleaner job, and you don’t have nearly the amount of fines that you do when the ’flowers are drier.”

Vern Hofman, extension ag engineer at North Dakota State University, agrees that good housekeeping is crucial to preventing fires while harvesting sunflower, just as it is while drying ’flowers in a high-temperature dryer. In both cases, he emphasizes, the potent combination of accumulated fines and high temperatures could lead to a very combustible — and downright expensive — dilemma.

Along with keeping the combine’s engine compartment as free of fines as possible, Hofman recommends growers regularly inspect any other area of the machine where fines and heat can come together. “If you have material building up on a drive shaft, alongside a bearing, it’ll get hot there, too,” he exemplifies.

Also, make sure all the electrical wiring is in good shape, the NDSU engineer advises. Wherever wire goes through sheet metal, for example, make sure there’s a rubber grommet around that hole in the metal. Should the wire’s insulation be worn off and the wire contacts the metal, the resulting arcing and sparks can ignite a fire if accumulations of fines are nearby, Hofman points out. — Don Lilleboe
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